Rapidly solidified powder has been produced by atomization techniques such as those described in U.S. Pat. No. 3,856,513. Powder produced by these techniques has a distribution in particle size, this variation in particle size gives rise to a variation in the cooling rate experienced by the particles, since the larger the particle the slower the particle cools.
More rapid quenching rates than obtained by atomization techniques may be obtained by splat quenching, such as taught in U.S. Pat. No. 4,221,587. Splat quenching, although in general, providing more cooling than the atomization techniques, produces powders where some of the powder has experienced different cooling rates.
More uniformly cooled powder quenched at the high rate associated with splat quenching techniques can be obtained by casting ribbon and subsequently fracturing it to form powder. Methods for reduction of ribbon to powder are taught in U.S. Pat. No. 4,290,808, however, these methods are not capable of a throughput of ribbon which is compatible with the output from a ribbon casting operation. For this reason the methods of the 4,290,808 patent are not well suited for integration into an in-line operation which produces ribbon that is to be converted to powder.